Fuentes was convicted of public health offences in a Spanish court on April 30, but a decision by judge Julia Patricia Santamaria to destroy evidence collected during the Puerto investigation hit expectations that any possible footballing former clients might be identified.

Convicted doper Armstrong told Le Monde that the set-up uncovered by the Puerto investigation was much bigger than anything he had been involved in, and claimed that important figures from Spanish football had leaned on the proceedings.

"I'm sure some big football clubs have had an influence on this decision," Armstrong said. "Anyway, it is still cycling, which was held to be solely responsible. We saw that the Puerto affair was a hundred times more sophisticated. Our system was very simple, very conservative, and not evil."

While Armstrong may have his own reasons for pointing a finger towards football and Spain, Fuentes has a long connection to other sports. The disgraced doctor admitted himself in court to having previously worked with footballers, tennis players, athletes and boxers, but the judge kept the trial's focus to cycling.

Rumours of the Canary Islander's work with top footballers have been common in Spain and elsewhere for years, but his only publicly acknowledged work was with his local side Las Palmas, who he helped get promoted to the Primera Division in 2000-01. He told Marca in April that he had worked for other "big" La Liga clubs, but that "death threats" forced him not to reveal which ones.

In 2009 both Real Madrid and Barcelona took a successful legal action to force Le Monde to withdraw a claim, made by Fuentes in a 2006 interview with the French paper, that he had worked for both La Liga's big two. Valencia and Real Betis were also mentioned in that article.

During this year's trial Madrid released a statement denying it had ever used Fuentes' services, after the doctor made an apparently offhand comment about the club not paying its debts to reporters outside the court.

Former Real Sociedad president Inaki Badiola told AS in February that Fuentes had worked for the Basque club in the past, and the code 'RSOC' appeared in documents relating to blood transfusions during the trial. La Real and its former president Jose Luis Astiazaran both quickly and angrily refuted any suggestion the club had ever employed Fuentes.

As doping was not a crime in Spain until recently, Fuentes and ex-cycling coach Ignacio Labarta were instead charged with and found guilty of carrying out medical procedures in an unsafe environment. Fuentes received a suspended one-year jail sentence, €4,500 fine and had his sports medicine license withdrawn for four years. Labarta got a four-month suspended sentence, and a smaller fine. Under Spanish law neither man will actually serve time in jail.

No significant progress has apparently been made in overturning the judge's decision to destroy the 211 bags of blood from 35 unknown sportspeople collected during the Puerto investigation.

However Spanish anti-doping agency [AEA] director Ana Munoz still holds out hope of getting access to them - "I am confident of knowing the names of all those implicated in Operacion Puerto," Munoz said in mid-June.

Munoz also said that she had rejected a suggestion from Fuentes, made during the trial, where he offered further "collaboration" in exchange for the charges being dropped.

After enduring a tricky start to his Manchester United career, perhaps it is fair that Marcos Rojo celebrated so boisterously as he watched his first professional club Estudiantes beat fierce rivals Gimnasia